The present invention relates to a new device for concentrating fish into a localized volume of an enclosure. It is particularly useful for attracting fish into a limited volume adjacent to the front panel of an aquarium where they can be more readily observed.
In aquariums and other fish-holding enclosures, fish tend to be fairly widely distributed throughout the contained volume of water. There is one exception to this general rule. In enclosures such as hatchery raceways, the stream dwelling species will frequently congregate in the vicinity of water inlets. This may possibly be due to the higher oxygen content of the water at this location. However, this phenomenon appears, at least in part, to be due to the natural tendency of stream dwelling fish to face in the direction of a flowing current. Scantlin, in U.S. Pat. No. 3,921,584, discloses a fish display device which, while not so restricted, could be installed on a hobbyist aquarium. This contains a maze and, optionally, a water impeller to produce a current flowing through the maze. The inventor states that the fish are thus encouraged to swim against the current.
Fish display and culture is very popular among home hobbyists. A significant industry has sprung up to supply appropriate species of fish and equipment to these hobbyists. Home aquariums generally hold between 10 and 50 gallons of water. It is essential to have additional support equipment such as circulating systems, aerators, and filters to maintain a healthy environment for the fish on a continuing basis. These purification systems will filter out or biologically degrade the waste products of the fish, uneaten food residues, and other organic contamination.
The bottom surface of an aquarium is usually covered with gravel. This serves as an anchoring matrix for plants which enhance the attractiveness of the aquarium setting and provide resting cover for the contained fish. The plants also serve as biological cleaning devices by metabolizing nitrogenous residues and by contributing oxygen to the water. The gravel also serves as a matrix for bacteria which assist the purification process.
As those who have observed aquariums are well aware, the fish seem to have a perverse tendency to hide at the very time the viewer would like to see them close up. The present device provides a solution to this problem.